[r-t] A new Spliced Surprise Major canon
mark at snowtiger.net
Wed Mar 6 21:42:37 UTC 2013
> Did you start with your six chosen methods from the very outset?
No. I knew I wanted to start with Bristol, to use the 5056 no.1, and I
knew I wanted methods that were (a) very good in their own right, but
also (b) well-known. I set up a shortlist, which included other stuff
like Yorkshire, Ashtead, Adelaide, Cat's Eye, Eleuthera, Heptonstall,
Lancashire and Xenon. I then carried out many exploratory searches to
find out which methods worked best.
In the earlier stages, in particular 2- and 3-spliced, it proved very
hard to find methods which would give competitive music. At the other
end of the scale, it started to become more difficult to achieve ATW.
But I am pleased with the final set of methods - they meet all the
objectives, whilst remaining a diverse bunch with a good spread of
backworks and leadhead orders.
> If I gave you, say, six "randomly" selected treble-dodging major
> methods (or 6 of the same leadhead group you used, or
> even slight tweaks like replacing Lessness with London (not that I'd
> advocate this!)), what are the chances of a true atw composition
> dropping out? With similar musical properties to your comps?
It probably depends on the cross-falseness and the leadhead groups, but
ATW is the most likely property to be achievable. However, you'd
probably need to find a different seed composition, and you're unlikely
to get anywhere near the same music counts. I think I've ended up with a
stand-out selection of methods, that go well together, and allow good
music to be exploited. OK, I'm sure you could make improvements with
methods deliberately constructed to optimise the music - but they might
not end up as interesting to ring.
> Is 6 methods the maximum you could get into an atw composition on this
> specific calling plan? Your message kind of implies you've tried to
> increase this?
No, I'm hopeful of adding further methods in. However with the current
version of the software I'm hitting some memory problems - the
cross-falseness tables can take 8GB of memory and more by the time I
reach 7 and 8 methods. I've got 16GB in my main desktop, but the
table-build time is a bit excessive, and its easy to run into GC or
page-faulting problems which kill the searches, especially if you want
to run more than one.
Since my modus operandi is based around relatively quick searches, which
I chain together after visually inspecting the results and tuning
parameters for the next iteration, the memory requirements and
table-build times start to become onerous over six methods. I'm working
on some improvements which should alleviate this; I've also got a
prototype which is meant to "double-up" the ATW of a single method, in
preparation for replacement of half its leads by a new method during a
second phase, which should provide another avenue to higher
> the new thing here is the series of methods with constraint of a fixed
> calling. I get a bit uneasy about constructed approaches as you're
> essentially condemned to a damage-limitation exercise
Well, I'm guessing the stochastic approach is new, although happy to be
corrected on that front (someone gave me the idea for applying simulated
annealing to spliced nearly twenty years ago, so it ought to have been
exercised before now!). You are right, I am trying to optimise the
result around a fixed framework, but I rather like that - it's the soul
of ringing really, isn't it?
> ...how applicable is your general metaheuristic approach to other more
> "architectured" ringing problems, where say the calling may be fixed but
> instead the method choice is open?
Very much so, although the software would need to have major
adaptations. You're looking at searching place notations not spliced
> 1) Getting methods for a whole-course 23-spliced major, along the lines of
> what Richard Smith did at: ...
Definitely, although looking at Richard's post it seems he did use some
kind of stochastic algorithm. I don't know by what extent it would be
possible to improve his on work.
> 2) Starting with say Alan Reading's recent 8-part major with all the runs,
> knowing you wanted to replace 3 identified methods with replacements that
> would leave the composition true and with the same musical properties
Yep, definitely. Again, you'd need different software - as above, I'm
guessing it would be more a case of exploring the space of place
notations that make up the three replacement methods.
> 3) Producing an extent of spliced treble dodging major? (Either
> "conventional" spliced, or 180 whole courses, or a 7-part with 180 leads
> per part)
You can have one of those once you've rung the Helixoid/PB extent. :-D
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